Wireless Local Area Networks (WLANS) have become ubiquitous. Typically, a single channel is used for wireless communication in WLANs, which is accessed through, among others, a distributed MAC protocol. [IEEE 802.11 standard] WLANS can include multiple channels and multiple radios. An approach that offers both multi-channel and multi-radio capabilities appears in the co-pending patent application titled “A Protocol For Wireless Multi-Channel Access Control”, Attorney docket number AVA06-01, filed Mar. 29, 2006, the disclosure of which is incorporated by reference herein, which describes the CCC (Common Control Channel) MAC protocol. CCC utilizes two types of logical channels, the control channel and the data channels.
In wireless Local Area Networks (LANS), a wireless channel can be reserved for the transmission of a sequence of frames while employing asynchronous distributed random channel access methods. In such an environment, both the source and destination of the transmission broadcast the reservation duration in order to establish the interference neighborhood.
According to the 802.11 distributed channel access MAC protocol, RTS/CTS frames are used to notify neighbors of a transmission. The source and destination of the transmission send the RTS and CTS control frames, respectively, which contain the reservation duration in order to establish the interference neighborhood. Nodes receiving either control frame refrain from transmitting or agreeing to receive a transmission for the specified duration.
One method of reserving the channel and preventing collisions with hidden terminals in wireless LANS is by utilizing frame-by-frame reservation. RTS/CTS frames are sent at the start of the reservation. The reservation time is extended on a frame-by-frame basis, by updating the duration of the reservation with each data frame and the acknowledgement that follows. A consequence of frame-by-frame reservation if that, if the reservation is not accepted—that is, a CTS frame is not returned in tine—there is no reserved time left unused and, hence, the reservation does not require cancellation.